package com.jiajia.server.config.security.compontent;

import io.jsonwebtoken.*;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * Jwt工具类
 * @author ZSJia
 * @date 2021/8/10 010 - 14:34
 */
@Component
public class JwtTokenUtils {
        //载体用户名
    private static final String CLAIN_KEY_USERNAME="sub";
        //载体创建时间
    private static final String CLAIN_KEY_CREATIME="create";


    //密钥
    @Value("${jwt.secret}")
    private  String secret;
    //过期时间
    @Value("${jwt.expiration}")
    private Long  expiration;


    //根据用户信息生成token
    public String generateToken(UserDetails userDetails){
        Map<String,Object> claims  = new HashMap<>();
        claims.put(CLAIN_KEY_USERNAME,userDetails.getUsername());
        claims.put(CLAIN_KEY_CREATIME,new Date());
        return generateToken(claims);
    }

    /**
     * 根据token获取用户名
     * @param token
     * @return
     */
    public String getUserNameFromToken(String token){
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username =   claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }

    /**
     * 根据token获取荷载
     * @param token
     * @return
     */
    private Claims getClaimsFromToken(String token) {
        Claims claims = null;
        try {
            claims = Jwts.parser()
                   .setSigningKey(secret)
                   .parseClaimsJws(token)
                   .getBody();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return claims;
    }

    /**
     * 判断token是否过期
     * @param token
     * @param userDetails
     * @return
     */
   public boolean validateToken(String token,UserDetails userDetails){
       String username = getUserNameFromToken(token);
       return   username.equals(userDetails.getUsername()) && !isTokenExpired(token);
   }

    /**
     * 判断token是否失效
     * @param token
     * @return
     */
    private boolean isTokenExpired(String token) {
        Date expiredDate =  getExpiredDateFromToken(token);
        return expiredDate.before(new Date());
    }

    /**
     * 判断token是否可以刷新
     * @param token
     * @return
     */
    public boolean canRefresh(String token){
        return isTokenExpired(token);
    }

    /**
     * 刷新token
     * @param token
     * @return
     */
    public  String RefreshToken(String token){
        Claims claims = getClaimsFromToken(token);
        claims.put(CLAIN_KEY_CREATIME,new Date());
        return  generateToken(claims);
    }
    /**
     * 获取失效时间
     * @param token
     * @return
     */
    private Date getExpiredDateFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return  claims.getExpiration();
    }

    /**
     * 根据荷载生成token
     * @param claims
     * @return
     */
    private String generateToken(Map<String,Object> claims) {
        return Jwts.builder()
                            .setClaims(claims)
                            .setExpiration(generateExpirationDate())
                            .signWith(SignatureAlgorithm.HS512,secret)
                            .compact();
    }

    /**
     * 处理失效时间
     * @return
     */
    private Date generateExpirationDate() {

        return new Date(System.currentTimeMillis()+expiration*1000);

    }


}
